WM_NCLBUTTONDOWN  1D_G_SZ 

The WM_NCLBUTTONDOWN message is posted when the user presses the left mouse button while the cursor is within the nonclient area of a window. This message is posted to the window that contains the cursor. If a window has captured the mouse, this message is not posted.

WM_NCLBUTTONDOWN

nHittest = (INT) wParam;    // hit-test value

pts = MAKEPOINTS(lParam);   // position of cursor

 

Parameters

nHittest

Value of wParam. Specifies the hit-test value returned by the DefWindowProc32D1NBH function as a result of processing the WM_NCHITTEST message. For a list of hit-test values, see WM_NCHITTEST1_TNZJB.

pts

Value of lParam. Specifies a POINTS24H.4H structure that contains the x- and y-coordinates of the cursor. The coordinates are relative to the upper-left corner of the screen.

 

Return Values

If an application processes this message, it should return zero.

Default Action

The DefWindowProc function tests the given point to find out the location of the cursor and performs the appropriate action. If appropriate, DefWindowProc sends the WM_SYSCOMMAND message to the window.

Remarks

An application can use the MAKEPOINTS macro to convert the lParam parameter to a POINTS structure.

See Also

DefWindowProc, MAKEPOINTS, POINTS, WM_NCHITTEST, WM_NCLBUTTONDBLCLK, WM_NCLBUTTONUP, WM_SYSCOMMAND